1. Field of the Invention
The present invention relates to an electrode structure and the fabrication method thereof, and more particularly to an electrode structure adapted for high applied voltage and the fabrication method thereof.
2. Description of the Related Art
FIG. 1a is a diagram schematically illustrating an electrode plate 100 with nearby electrode plates 200 and 300. When a voltage difference across electrode plates 100 and 200 or electrode plates 100 and 300 is substantially high, an electric discharge through the dielectric material such as air or vacuum, a phenomenon known as arcing, may happen. The arcing path from electrode plate 200 to 100 is referred as an upper arcing path; and from electrode plate 300 to 100 is referred as a lower arcing path. The upper and lower arcing paths form a single equivalent circuit which is illustrated in FIG. 1b, wherein capacitor C100/200 and C100/300 represent the parallel plate capacitor formed by electrode plate 100 and 200, and the parallel plate capacitor formed by electrode 100 and 300 respectively; and resistor R100, in series with C100/200 and C100/300 in the respective arcing paths, represents the resistance of the electrode plate 100, which is made of aluminum for instance. Considering the upper arcing path for example, when a voltage Vu is applied to the electrode plate 100, the voltage across C100/200 may exceed the breakdown voltage of the dielectric therebetween, resulting in arcing, which can be considered as a short of C100/200. Since resistance of R100 made of metal is small, high amount of current therethrough may cause the electrode function to fail. Hence, the electrode plate 100 is commonly made of refractory metals which have high breakdown voltages, such as titanium Ti, tungsten W, or graphite, or metals treated with surface modification in order to prevent high voltage breakdown.
However, even with electrodes made of high breakdown voltage materials, possible power failure caused by arcing is still unresolved. Therefore, there is a need to prevent arcing from happening while maintaining the electrode plate to be conductive.